diff --git a/data/shaders/combine_diffuse_color.frag b/data/shaders/combine_diffuse_color.frag
index f2dee049c..df7f34e86 100644
--- a/data/shaders/combine_diffuse_color.frag
+++ b/data/shaders/combine_diffuse_color.frag
@@ -23,7 +23,8 @@ void main()
     vec3 DiffuseComponent = texture(diffuse_map, tc).xyz;
     vec3 SpecularComponent = texture(specular_map, tc).xyz;
 
-    vec3 metallicMatColor = mix(vec3(0.04), diffuseMatColor.xyz * 4, metallicMapValue);
+    vec3 diffuse_color_for_mix = diffuseMatColor.xyz * 4.0;
+    vec3 metallicMatColor = mix(vec3(0.04), diffuse_color_for_mix, metallicMapValue);
     vec3 tmp = DiffuseComponent * mix(diffuseMatColor.xyz, vec3(0.0), metallicMapValue) + (metallicMatColor * SpecularComponent);
 
     vec3 emitCol = diffuseMatColor.xyz * diffuseMatColor.xyz * diffuseMatColor.xyz * 15.;